Daikin FTXS09HVJU Service Manual page 61

SiUS04-904
Indoor Frequency Command (D signal)
The difference between a room temperature and the temperature set by the remote controller is
taken as the "D signal" and is used for frequency command.
Th OFF = Thermostat OFF
Frequency Initial Setting
<Outline>
When starting the compressor, or when conditions are varied due to the change of the room, the
frequency must be initialized according to the total of a maximum D value of the indoor unit and
the Q value of the indoor unit.
Q value: Indoor unit output determined from indoor unit volume, air flow rate and other factors.
PI Control (Determine Frequency Up/Down by D Signal)
1. P control
2. I control
3. Limit of frequency variation width
4. Frequency management when other controls are functioning
 When frequency is
 For limiting lower limit
5. Upper and lower limit of frequency by PI control
Function and Control
D
Temperature Temperature
difference signal difference
Th
0
OFF
0.5 1
1.0 2
1.5 3
Calculate D value in each sampling time (20 seconds), and adjust the frequency according to
its difference from the frequency previously calculated.
If the operating frequency is not change more than a certain fixed time, adjust the frequency up
and down according to the D value.
When the D value is small...lower the frequency.
When the D value is large...increase the frequency.
When the difference between input current and input current
the frequency increase width must be limited.
dropping
Frequency management is carried out only when the frequency drops.
Frequency management is carried out only when the frequency rises.
The frequency upper and lower limits are set depending on indoor unit.
When low noise commands come from the indoor unit or when outdoor unit low noise or quiet
commands come from indoor unit, the upper limit frequency must be lowered than the usual
setting.
D
Temperature
signal difference
2.0 4 4.0
2.5 5 4.5
3.0 6 5.0
3.5 7 5.5
;
Control Specification (15/18/24 Class)
D
Temperature
signal difference
8 6.0
9 6.5
A 7.0
B 7.5
dropping value is less than 1.5 A,
D
signal
C
D
E
F
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